# Metformin and Levoquin interaction **URL:** \ **Category:** Factual Questions\ **Created:** [March 17, 2010, 3:55pm UTC](https://boards.straightdope.com/t/metformin-and-levoquin-interaction/532759 "2010-03-17T15:55:23Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Canadjun](https://avatars.discourse-cdn.com/v4/letter/c/76d3ee/32.png) [@Canadjun](https://boards.straightdope.com/u/Canadjun)\ **Post date:** [March 17, 2010, 3:55pm UTC](https://boards.straightdope.com/t/metformin-and-levoquin-interaction/532759/1 "2010-03-17T15:55:23Z")
Yes, this is a medical question that I probably should have had my doctor dig up more details about, but I think it is kosher here because I have been taking Metformin for years and Levaquin numerous times during that period without ill-effect. My doctor has mentioned a couple of times when I’ve had Levaquin prescriptions that it apparently can interact with Metformin, but he didn’t mention specific symptoms. Do the professionals in the audience happen to know what the interaction supposedly is? I tried googling and I can’t find any mention of the two interacting. ---
**Author:** ![Mama\_Zappa](https://avatars.discourse-cdn.com/v4/letter/m/71e660/32.png) [@Mama\_Zappa](https://boards.straightdope.com/u/Mama_Zappa)\ **Post date:** [March 17, 2010, 5:07pm UTC](https://boards.straightdope.com/t/metformin-and-levoquin-interaction/532759/2 "2010-03-17T17:07:50Z")
[drugs.com](http://drugs.com) has a good interactions checker - you plug in all your drugs and they point out any interactions. From there: > [@](#): > > MONITOR: Quinolone antibiotics may interfere with the therapeutic effects of oral antidiabetic agents and insulin. The use of certain quinolones such as clinafloxacin, gatifloxacin, temafloxacin, levofloxacin, and moxifloxacin has been associated with disturbances in blood glucose homeostasis possibly stemming from effects on pancreatic beta cell ATP-sensitive potassium channels that regulate insulin secretion. Hypoglycemia and, less frequently, hyperglycemia have been reported during use of quinolones, although the latter may also occur due to underlying infection alone. Coadministration of sulfonylureas (most often glyburide) and/or other oral hypoglycemic agents with ciprofloxacin, norfloxacin, and especially gatifloxacin has occasionally resulted in severe, refractory hypoglycemia and hypoglycemic coma. Elderly patients and patients with reduced renal function are particularly susceptible. Ciprofloxacin may also inhibit the hepatic metabolism of glyburide. Hypoglycemia in association with elevated serum glyburide level occurred in a patient after one week of ciprofloxacin therapy. > > MANAGEMENT: Blood glucose should be monitored closely whenever quinolones are prescribed to patients receiving oral antidiabetic agents and/or insulin, especially if they are elderly or have renal impairment. Patients should be counseled to recognize symptoms of hypoglycemia such as headache, dizziness, drowsiness, nausea, tremor, weakness, hunger, excessive perspiration, and palpitations. If hypo- or hyperglycemia occur during quinolone therapy, patients should initiate appropriate remedial therapy immediately, discontinue the antibiotic, and contact their physician. FWIW, I have a number of “moderate” interactions on medications I take, and have never had problems with them. It’s something to keep an eye on, however. ---
**Author:** ![Ionizer](https://avatars.discourse-cdn.com/v4/letter/i/5daacb/32.png) [@Ionizer](https://boards.straightdope.com/u/Ionizer)\ **Post date:** [March 17, 2010, 5:33pm UTC](https://boards.straightdope.com/t/metformin-and-levoquin-interaction/532759/3 "2010-03-17T17:33:23Z")
It has been my experience that pharmacists are generally MUCH more knowledgeable than physicians on the ins & outs of the medicines. Not always, of course…but it is right up their alley 🙂 Also, I assume that you read all the tiny print on the medication’s ‘info insert’ (if you were given such - if not, get it in writing, so to speak, from the pharma person). I forget what that piece of paper is called, but usually there is a VERY exhaustive list of known interactions and other tidbits that may help answer this for you. I am not speaking of the printout sometimes received that says typical “call Doc if any problems/take as directed/don’t drive if affecting you/etc”, but the one with technical product info that often requires a magnifying glass to read it all. ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [March 17, 2010, 6:29pm UTC](https://boards.straightdope.com/t/metformin-and-levoquin-interaction/532759/4 "2010-03-17T18:29:02Z")
Levaquin-Metformin interactions > [@](#): > > Levofloxacin > > 1. Interaction Effect: changes in blood glucose and increased risk of hypoglycemia or hyperglycemia > 2. Summary: Changes in blood sugar and hypo- or hyperglycemic episodes have been reported when fluoroquinolones were used with antidiabetic agents. The concurrent administration of levofloxacin, a quinolone antibiotic, and antidiabetic agents has been reported to cause alterations in blood glucose (both hyperglycemia and hypoglycemia). When these agents are coadministered, it is recommended that the patient’s blood glucose be closely monitored (Prod Info Levaquin(R), 2000). Episodes of clinically significant hypoglycemia and hyperglycemia have been reported in the postmarketing period in patients treated concomitantly with gatifloxacin in conjunction with both sulfonylurea and non-sulfonylurea antidiabetic agents (Biggs, 2003a; Baker & Hangii, 2002a). Hypoglycemic episodes usually occurred within 1 to 3 days of beginning therapy with gatifloxacin. Hyperglycemia, in some cases severe, occurred usually after the third day of gatifloxacin treatment. The manufacturer further warns that the use of gatifloxacin is contraindicated in patients with diabetes mellitus (Bristol-Myers Squibb, 2006). The concurrent administration of ciprofloxacin and glyburide has caused severe hypoglycemia, resulting in fatalities in some patients (Prod Info Cipro(R) XR, 2003; Lin et al, 2004). The concurrent administration of other fluoroquinolones and oral hypoglycemic drugs such as glyburide has resulted in potentiation of the hypoglycemic effect of these drugs (Prod Info Floxin(R), 2000). > 3. Severity: major > 4. Onset: rapid > 5. Substantiation: established > 6. Clinical Management: If concurrent therapy with a fluoroquinolone and an antidiabetic agent is necessary, closely monitor the blood glucose level and adjust the dose of the antidiabetic agent as indicated; dose adjustment may be required after discontinuation of a fluoroquinolone. If a hypoglycemic reaction occurs, the patient should initiate appropriate therapy immediately, discontinue the fluoroquinolone, and contact a physician. > 7. Probable Mechanism: unknown Micromedex ---
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [March 17, 2010, 6:30pm UTC](https://boards.straightdope.com/t/metformin-and-levoquin-interaction/532759/5 "2010-03-17T18:30:53Z")
I believe this is a typical “CYA” type of statement. That is, _another_ antibiotic, called gatifloxacin, _was_ associated with deranged blood sugar levels (and was actually since taken off the market). [Here is the relevant paper](http://content.nejm.org/cgi/content/abstract/354/13/1352) which led to gatifloxacin’s removal. Other than that bizarre and indirect “interaction”, there is none of which I am aware (and that includes searching a drug interaction site as well as a PubMed search) ---
**Author:** ![Canadjun](https://avatars.discourse-cdn.com/v4/letter/c/76d3ee/32.png) [@Canadjun](https://boards.straightdope.com/u/Canadjun)\ **Post date:** [March 17, 2010, 7:23pm UTC](https://boards.straightdope.com/t/metformin-and-levoquin-interaction/532759/6 "2010-03-17T19:23:58Z")
Thanks! Like I said, I haven’t had any weird reactions from taking both together; I was just curious. ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [March 17, 2010, 7:33pm UTC](https://boards.straightdope.com/t/metformin-and-levoquin-interaction/532759/7 "2010-03-17T19:33:54Z")
> [@Mama\_Zappa](#): > > [drugs.com](http://drugs.com) has a good interactions checker - you plug in all your drugs and they point out any interactions. OMG, **Mama Zappa** , that’s awesome. ---
**Author:** ![3waygeek](https://avatars.discourse-cdn.com/v4/letter/3/e95f7d/32.png) [@3waygeek](https://boards.straightdope.com/u/3waygeek)\ **Post date:** [March 18, 2010, 3:23pm UTC](https://boards.straightdope.com/t/metformin-and-levoquin-interaction/532759/8 "2010-03-18T15:23:25Z")
> [@KarlGauss](#): > > I believe this is a typical “CYA” type of statement. That is, _another_ antibiotic, called gatifloxacin, _was_ associated with deranged blood sugar levels (and was actually since taken off the market). [Here is the relevant paper](http://content.nejm.org/cgi/content/abstract/354/13/1352) which led to gatifloxacin’s removal. Other than that bizarre and indirect “interaction”, there is none of which I am aware (and that includes searching a drug interaction site as well as a PubMed search) Note that gatifloxacin is still available for opthalamic use, under the brand name Zymar. I’ve used it a couple times in recent years, including as recently as a month ago.